Grinding apparatus and method



June 17, 1930. RODEMEYER 1,763,820

GRINDING APPARATUS AND METHOD Filed Aug. 4, 1928 INVENTOR.

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Patented June 17, 1930 may RODEMEYER,

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01 DETROIT, MICHIGAN, ASSIGNOR TO BARNES-GIBSON-RA'Y- DETROIT, MICHIGAN,A CORPORATION OF MICHIGAN enrnnme s rrsna'rus Ann mnrnon Applicationfiled August 4,1928. Serial No. 297,429.

This invention relates to the art of grinding and has to do' especiallywith the grinding of sharp edges from articles of manufacture such ascoil springs, which grinding 5 is in the nature of a finishing process.

The invention has as an object the obtaining of an increased rate 1 ofproduction a 1n thegrinding of such articles by utilizing soft materialwhich has a relatively rapid grinding action. Such grinding materialhowever. is subject to relatively rapid wear, and

the invention contemplates protecting this .grinding material to preventunduly rapid wearing away of the material.

In" this regard other grinding material is provided which is relativelyhard and which does not rapidly wearaway. The hard ma- I terial does notgrind so'factas the soft material, but this material is used to form' aninitial grinding action which removes burrs or sharp points from thearticle so that these sharp points will not dig into and unduly wearaway the relatively soft grinding material. f

It is known that soft grinding material effects a grinding action morerapid than a hard grinding material, but that the soft material wearsaway much more rapidly. The theory of this is that a softer binder isused in the soft grinding material which wears away and exposes theabrasive element, whereas in the hard grinding material a hard binder isused which does not wear away so rapidly and which does not expose theabrasive element to such a high degree.

- In'the accompanying drawings:

Fig. 1 is'a side elevational view of a grinding apparatus constructedfor carrying out the invention. 7

on the line 2- 2 of Fig; 1

In thesedrawings'there is shown a grind ingwheel 1 mounted upon shaft 2,and an opposed grinding wheel on shaft 4.

(notlshown) operably connected to their r'e the articles through Thearticles may be fed to the chain byhand Fig. 2'isa'compositesection andplan taken in the rough, are at anangle to the axle of;

Th grindingwheelsarerotated preferabl'yiat lilll l form speeds byanysuitable power mechanism The grinding wheels may advantageousl consistof two kinds of grinding materiai one of which is disposed near theperiphery of the wheel, as shown at 5, and the other of which isdisposed centrally of the wheel, as at The articles to be ground are fedthrough the two opposed grindin wheels so that the two wheels may actsimu taneously-upon opposite sides or ends of the articles. For thispurpose there is a power driven conveyor which moves the articlesbetween the grinding wheels, and this conveyoris shown as beingin theform of an endless chain v7, which moves over suitable sprockets (notshown). Some of-the links of the chain are enlarged, as at 8, andprovided with openings 9 for receiving and holding the articles.

The articles are shown as coil springs 10. This conveyor moves fromright to left in the operation ofthe apparatus and there may be guidedevices 11 and 12 each formed with flared portions 13 and 14 forengaging the endsof the springs to center the same and guide them inbetween the grinding wheels.

. In the operation of this apparatus the grinding wheels are set inmotion and the conveyor moves from right to left carrying the grindingwheels.

.80 or suitable automatic means, and they may be removed from the chainafter the grin ing operation by hand or automatic means. This chainconveyor is used largely for exemplaryv purposes and it is to beunderstood that other means for conveyors can be used for moving thesprings through the grinding wheels.

It will be understood that the plane of the ends of such springs, whenthe springs are are rendered perpendicular or; substant1ally 1 96 1"perpendicular to the axis of the spring so that; A they can he betterused. I In grinding springs it has been foundthafl'l ends, of thespringswhile in the roughfare,

duite'sharp and 'oft'time s have rough burrs m perh or projectionsthereon. These sharp points dig into relatively soft grinding materialwith the result that there is an unduly rapid wear on the grindingwheel. However, it is desirable to use relatively soft grinding materialbecause it grinds faster and the production accordingly increased.

In order to take advantage of the more rapid grinding action of thegrinding material, and at the same time to eliminate the disadvantage ofunduly rapid wear of this material, the invention contemplates apreliminary grinding of the springs by a hard grinding material. One wayof accomplishing this is by constructing the grinding wheels with aplurality of sections made up of different grinding materials.

Accordingly the grinding material 5 is hard, and as the springs firstenter between the grinding wheels the spring ends are ground by thesection 5. This removes sharp burrs or corners on the ends of thesprings but the grinding action is not so rapid. The springs then passon further in between the grinding wheels where they are engaged by thesections 6 which are composed of softer material.

Thus the hard material 5 removes the sharp points or burrs and thusafiords protection for the material 6. The material in section 5 beinghard does not grind so rapidly, while the material in, section 6 issofter but has a rapid grinding action. Accordingly, high production isobtained while at thesame time the rapidly acting grinding material isnot unduly worn away.

There has been shown in the drawings grinding wheels composed of anexterior strata of hard grinding material with an inner layer of softgrinding material. This aps shows the invention in its simplest form,but it is well within the invention to employ more than two differenttypes of grinding material; for example, the grinding wheels may beprovided with three layers arranged thusly: hard grinding material whichfirst grinds the sharp points from the articles and Which'is located atthe rim of the wheel, and an intermediate layer of grinding material ofmedium hard substance, and then an inner layer of the softer grindingsubstance. This is intended to be covered by the claims appended hereto.

, Thus several different layers of the grinding material of differentgrades, the first to act upon the spring being a hard grade, thesucceeding material being of softer grade. Also the grain of thegrinding material can be varied, and it is preferable to have a finegrained grinding substance for first acting upon the'articles with thecoarser grained grilnding substance later acting upon the artic e.

What I claim is: 1. An apparatus for grinding articles,

comprising in combination, a grinding element composed of grindingmaterial which has relatively great resistance to wear, another grindingelement composed of grinding material which has relatively lowresistan'ce to wear but which effects a grinding action relatively greatas compared to the grinding action of the first element, means forcarrying an article to be ground past the said grinding elements in theorder named, whereby the first mentioned element removes burrs or sharpprojections from the articles to prevent undue wearing away of thesecond named grinding element.

2. A spring grinding apparatus for grinding the ends of coil springs,comprising in combination, a pair of opposed grinding elements composedof grinding material which as relatively great resistance to wear, asecond pair of opposed grinding elements composed of grinding materialof relatively low resistance to Wear but which effects a grinding actionrelatively great as compared to the grinding action of the firstmentioned pair of elements, and means for carrying a spring between thepairs of grinding elements in the order in which they are named, wherebythe first mentioned elements remove burrs or sharp projections from theends of the springs to prevent undue wearing away of the second pair ofgrinding elements.

3. A spring grinding apparatus for grinding the end of a coil spring,which comprises a grinding wheel composed of an outer section ofgrinding material having relatively great resistance to wear, and aninner section composed of grinding material possessing relatively lowresistance to wear but which eifects a relatively rapid grinding action,means for carrying the spring past the grinding wheel so that the springis first ground by the outer section and then by the inner section,whereby the outer section first removes burrs or sharp projections fromthe springthus to prevent unduly rapid wearing away of the innersection.

4. A spring grinding apparatus for grinding the ends of coil springs,comprisin in combination, wheels disposed in spaced relation, eachgrinding wheel being made up of an outer section which is composed'ofgrinding material which possesses relatively great resistance to wear,and an inner section composed of grinding material which possessesrelatively low resistance to wear, but which effect a relatively rapidgrinding action, and means for passing a spring between the grindingwheels whereby the ends of the spring are first ground by the highresistant grinding material to remove burrs 'or sharp projectionstherefrom thus to prevent undue wearing away of the grinding material inthe inner sections.

a pair of opposed grin ing first grinding the article with the grindingmaterial, which, while eliecting a relatively slow grinding actionpossesses high resistance towear, to remove burrs or sharp projectionsfrom the articles before the article is acted upon by the firstmentioned material.

6. The method of expediting the production in the grinding of ends ofcoil springs, which comprises utilizing grinding material which efiectsa relatively rapid grinding action but which is subject to rapid wear,and preventing unduly rapid wear of this material by first grinding thespring ends with material, which, while efiectingl relatively slowgrinding action possesses igh resistance to wear, to remove burrs andsharp points from the spring ends.

In testimony whereof I aflix my signature.

HARRY RODEMEYER.

d grinding action but i of this material by'

